Polycarbonate resins are generally produced using bisphenols as a monomer ingredient, and are being extensively utilized as so-called engineering plastics in the fields of electrical and electronic parts, automotive parts, medical parts, building materials, films, sheets, bottles, optical recording media, lenses, etc. so as to take advantage of the superiority thereof such as transparency, heat resistance, and mechanical strength.
However, the conventional polycarbonate resins deteriorate in hue, transparency, and mechanical strength when used over a long period in places where the resins are exposed to ultraviolet rays or visible light. There hence have been limitations on outdoor use thereof and on use thereof in the vicinity of illuminators. Furthermore, use of the conventional polycarbonate resins as various molded articles has encountered a problem that the polycarbonate resins show poor mold release characteristics during melt molding and it is difficult to use the resins as transparent materials, optical materials, or the like.
Techniques in which a benzophenone-based ultraviolet absorber, benzotriazole-based ultraviolet absorber, or benzoxazine-based ultraviolet absorber is added to a polycarbonate resin in order to overcome such problems are widely known (see, for example, non-patent document 1).
However, addition of such an ultraviolet absorber poses the following problems although the addition brings about improvements in hue retention through ultraviolet irradiation, etc. Namely, there have been problems, for example, that the addition of the ultraviolet absorber deteriorates the hue, heat resistance, and transparency which are inherent in the resin and that the ultraviolet absorber volatilizes during molding to foul the mold.
Known as light stabilizers are hindered amine-based light stabilizers. However, polycarbonate resins are unstable to basic ingredients, e.g., alkalis, even at ordinary temperature, and it has been reported that polycarbonate resins are hydrolyzed by hindered-amine compounds also (see, for example, non-patent document 2). It is hence widely known that addition of hindered amine-based light stabilizers to polycarbonate resins is impracticable (see, for example, non-patent document 1).
The bisphenol compounds for use in producing conventional polycarbonate resins have a benzene ring structure and hence show high absorption of ultraviolet rays. This leads to a deterioration in the light resistance of the polycarbonate resins. Consequently, use of monomer units derived from an aliphatic dihydroxy compound or alicyclic dihydroxy compound which has no benzene ring structure in the molecular framework or from a cyclic dihydroxy compound having an ether bond in the molecule, such as isosorbide, is expected to theoretically improve light resistance. In particular, polycarbonate resins produced using, as a monomer, isosorbide obtained from biomass resources have excellent heat resistance and mechanical strength, and many investigations thereon hence have come to be made in recent years (see, for example, patent documents 1 to 7).
It is also widely known that benzotriazole, benzophenone, and cyanoacrylate compounds are added as ultraviolet absorbers to polycarbonate resin compositions obtained using a monomer having an ether bond in the molecule, such as isosorbide, isomannide, or isoidide, which each has no benzene ring structure in the molecular framework (see, for example, patent document 8).